Single or multipole push button actuated excess current switch having thermal and/or electromagnetic trip

ABSTRACT

A SINGLE OR MULTIPLE PUSH BOTTON ACTUATED EXCESS CURRENT SWITCH HAVING A THERMAL AND/OR ELECTROMGANETIC TRIP. IN THIS SWITCH THE PUSH BUTTON IS CONNECTED TO A CONTACT BRIDGE BY MEANS OF A LEVER ARRANGEMENT. THE LEVER CONNECTED TO THE CONTACT BRIDE IS PIVOTED ABOUT A PIN WHIH IS MOVEABLE IN A GROOVE. THIS GROOVE IS PROVIDED WITH A DETENT WHICH IS ENGAGED BY THE PIN DURING SWITCHING ON. THE LEVER CONNECTED TO THE CONTACT BRIDGE IS PROVIDED WITH A PROTUBERANCE WHICH CO-OPERATES WITH A STOP ON THE HOUSING OF THE SWITCH TO RAISE THE PIN TO DISENGAGE FROM THE DETENT TO THEREBY CAUSE INSTANTANEOUS SWITCHING ON OF THE SWITCH.

D06. 12, 1912 ELLENBERGER 3,106,057

' SINGLE 0R MULTIPOLE PUSH BUTTON ACTUATED EXCESS CURRENT SWITCH HAVING THERMAL AND/QR ELECTROMhGNETIC TRIP Filed Dec. 29, 1971 4 Sheets-Sheet 1 Dec. 12, 1972 J. ELLENBERGER SINGLE OR MULTIPOLE PUSH BUTTON ACTUATED EXCESS CURRENT 4 Sheets-Sheet 2 Filed Dec. 29,

Fig.2

w- 7 .J. ELLENBERGER 3, 0 ,057

I SINGLE OR MULTIPOLE PUSH BUTTON ACTUATED EXCESS CURRENT- SWITCH HAVING THERMAL AND/OR ELECTROMAGNETIC TRIP Filed Dec. 29, 1971 4 Sheets-Sheet 5 Fig.3

n. 1 2. 1912 J. ELLENBERGER 3.106.051

SINGLE 0R MULTIPOLE PUSH BUTTON ACTUATED EXCESS CURRENT SWITCH HAVING THERMAL AND/0R ELECTROMAGNETIC TRIP 4 Sheets-Sheet 4 Filed Dec. 29, 1971 1Fig.4

United States Patent C) US. Cl. 335-23 9 Claims ABSTRACT OF THE DISCLOSURE A single or multipole push button actuated excess current switch having a thermal and/or electromagnetic trip. In this switch the push button is connected to a contact bridge by means of a lever arrangement. The lever connected to the contact bridge is pivoted about a pin which is moveable in a groove. This groove is provided with a detent which is engaged by the pin during switching on. The lever connected to the contact bridge is provided with a protuberance which co-operates with a stop on the housing of the switch to raise the pin to disengage from the detent to thereby cause instantaneous switching on of the switch.

The invention relates to a single or multipole, push button actuated excess current switch having thermal and/ or electromagnetic trip and more especially to a switch which also includes a contact bridge connected to the push button by means of an elbow lever whereof the lever associated with the push button is in the form of a two-armed bell crank pivotably mounted by means of a bearing pin guided for transverse movement in grooves of the switch housing, whereof the free arm is supported by a dog adapted to be shifted by the thermal and/or electromagnetic trip, and whereof the lever associated with the contact bridge is articulatedly connected to the contact bridge by means of a pin guided for transverse movement in grooves of the switch housing, and having a fixed pivotably mounted latch which, when the switch is in the on" position, directly supports the bearing pin of that lever of the elbow lever which is associated with the push button, and which latch is connected to the elbow lever by means of a trip spring serving to break the elbow lever which latter forms an obtuse angle in the switched on position, the angle diminishing upon tripping.

A single-pole excess current switch of this kind is known which possesses both instantaneous disconnection and instantaneous connection. For the instantaneous connection a one-armed lever is guided, by means of a closed elongate slot, on the pin connecting the contact bridge with the associated lever of the elbow lever, which one-armed lever has at its end remote from the connecting pin a retaining nose which in the disconnected position of the contact bridge lies within the range of movement of a fixed stop and comes to adhere to the fixed stop during the switching on movement and can be caused by the elbow lever to disengage from the stop at the end of the pivoting movement of that lever of the elbow lever which 3,706,057 Patented Dec. 12, 1972 ICC is associated with the contact bridge. The one-armed lever disposed on the connection pin represents an additional structural element which has to be moved along when switching.

According to the present invention there is provided a single or multipole push button actuated excess current switch having a thermal and/or electromagnetic trip, such a switch comprising a housing, a contact bridge connected to the push button by means of a pivoted lever arrangement, the pivoted lever arrangement including first and second levers, the first and second levers being interconnected by means of a pin and slot arrangement, the first lever being associated with the push button and being in the form of a bell crank which is pivotably mounted by means of a first pin adapted to be guided for transverse displacement in a first groove of the housing, the first lever having a free end which is supported by a member which is adapted to be actuated by the thermal and/or the electromagnetic trip, the second lever being pivotally connected to the contact bridge by means of a second pin adapted to be guided for transverse movement in a second groove in the housing, the second groove being provided with a detent which is engaged by the second pin during switching on of the switch, the second lever being provided with a protuberance which is engageable with a stop on the housing to cause the second pin to be disengaged from the detent, a spring for biasing the second lever in the region of its interconnection with the first lever in a direction away from the first lever and a pivotally mounted latch plate which in the switched on position of the switch supports the first pin and which is connected to the lever arrangement so that upon tripping the first and second levers pivot relative to one another whereby the contact bridge is displaced to the switched off position of the switch.

In practice during switching on of the excess current switch the pin connecting the contact bridge with the second lever comes to abut the detent of the second groove, the contact bridge not yet being in the switched on position. By virtue of the pin/ slot connection of the two levers the latter can be further cocked. Thereby the protuberance of the second lever comes to abut the housing stop thus removing the pin from engagement with the detent. The spring biasing the second lever now causes a jerky movement of this lever and of the contact bridge which latter arrives at the switching on position. Thus this instantaneous connection is obtained in the present excess cur rent switch by comparatively simple means, i.e. by means of the detent in the guidance groove of the connecting pin. No additional mobile means are contemplated.

In one form of switch the spring is in the form of a torsion spring having one end supported on the first lever and the other end thereof in contact with the second lever.

Further, the switch may include a trip spring connected to the second lever, and a further torsion spring arranged on the pin of the pin and slot connection between the first and second levers, the further torsion spring having one end connected with the first lever and the other end thereof connected to the second lever.

In one form of switch a coupling lever is provided on the first pin, the said coupling lever being provided with an elongate slot engageable by a peg secured to a control rod which is rigidly connected to the push button, the

control rod having a protuberance at the end thereof remote from the push button, the said protuberance being adapted to engage an inclined surface of the latch in the switched on position of the switch.

In a preferred form the member adapted to be actuated by the thermal and/ or electromagnetic trip is in the form of a trip lever secured to a trip shaft, the trip lever having an indentation which is engageable by the said free arm of the first lever, the switch further including an arm in the form of a compensation bimetal strip which is secured to the trip and upon which a bimetal strip of the thermal trip is adapted to act.

Preferably the bimetal strip is U-shaped, with the two legs of the U being spaced so that they electrodynamically influence one another.

The housing may comprise two sections separated by a partition wall with the switching mechanism being disposed in one section and the trip mechanism being disposed in the other of the sections.

Preferably the two sections are provided with registering recesses in which the partition member is secured.

A preferred form of multipole excess current switch includes a plurality of housings each having a trip mechanism and a switching mechanism therein, one of the housings having a push button associated therewith, the first levers of all the housings having a common first pin which extends through all the housings, each housing further being provided with a trip shaft which is connected to the trip shafts of the other housings and those housings not being provided with a push button having a trip spring having one end engaged with the first lever and the other end thereof secured to its associated housing.

Illustrative embodiments of the invention will now be described with reference to the accompanying drawings, in which:

FIG. 1 shows a view of a lower housing section having arranged therein a switch mechanism in the switched on position of one form of excess current switch;

FIG. 2 shows a view of an upper housing section having arranged therein a bimetal strip of the thermal trip of the excess current switch partially illustrated in FIG. 1;

FIG. 3 shows a view similar to that of FIG. 1, with the excess current switch being in its switched off position;

FIG. 4 shows a section along line IVIV of FIG. 3;

FIG. 5 shows a side view of a multipole excess current switch; and

FIG. 6 shows a view of the right hand side of FIG. 5.

The excess current switch illustrated in FIGS. 1 to 4 comprises a housing of insulating material having an upper section 1 and a lower section 2. Both housing sections can be connected by hollow rivets engaging in registering bores 3. As can be seen in FIG. 4 the face to face superposed housing sections have recesses 4 and 5 registering with one another into which a partition wall 6 of insulating material is tightly inserted. The partition wall 6 divides the housing into two separate chambers 1' and 2'. The chamber 1' contains the switching mechanism and the chamber 2' contains the bimetal strip 7 of the thermal trip. The two-chamber system has the advantage that the bimetal strip 7 cannot be affected by arcing occurring in the switching mechanism.

Both FIGS. 1 and 2 show views of the two housing sections from below, the outer wall 8 of the upper section 2 being omitted in FIG. 2.

Terminals 9 and 10 are provided for the electrical connection. As shown in FIG. 2 a leg 11 of the U-shaped,

directly heated bimetal strip 7 is welded to the terminal 9. The other leg 12 ofthe bimetal strip 7 is in electrical connection with a copper wire 13 secured to a member 14 protruding into the chamber 1 and carrying a fixed contact 915. A further fixed contact 16 is secured to the terminal 10. Movable contacts 17 of a contact bridge 18 cooperate with the fixed contacts 15, 16. The contact bridge 18 is connected to a lever 20 by means of a pin 19. The lever 20 comprises two parallel plates connected by a cross member 21. The two plates of the lever 20 and the cross member 21 may be made in one piece from a synthetic material. Both plates of the lever 20 carry a pin 22 passing through a closed slot 23 of a lever 24 in the form of a bell crank. The two levers 20 and 24 form an elbow lever.

The lever 24 has a pin 25 guided for transverse displacement in corresponding grooves 26 of the housing. The pin 19 is also guided for transverse movement in grooves 27 of the housing. These grooves 27 are provided with a detent 28.

In the switched on position shown in FIG. 1 the pin 25 is supported by an angular indentation 29 of a latch 30 comprising two plates in spaced apart arrangement and connected by a cross member 31. The two plates of the latch 30 and the cross member 31 may be made of synthetic material in one piece. The latch 30 is pivotably mounted, by means of two lugs 32 unitarily moulded onto the plates, in corresponding bores of the housing. At a distance from the lugs 32 one end of a trip spring 33 engages the latch 30, the other end of the trip spring being hooked into an indentation 34 of the lever 24. An inclined surface 35 of the latch 30 is supported by a protuberance 36 disposed at the inner end of a control rod 37. The control rod 37 is formed from flat stock bent to an L-shape and secured by a rivet 3-8 to a push button 39 having an enlarged portion 40 for the purpose of manual tripping. At its lower end the control rod 37 is provided with a semicircular recess 41 and a drive member 42. The transverse leg of the L-shaped control rod 37 supports a spring 43 the lower end of which surrounds a lug 44 of the partition wall 6 so that it is secured to that wall. The lower end of the push button 39 is surrounded by a ring 45 of a colour different from the colour of the push button. In the switched ofi position shown in FIG. 3 the push button 39 with the ring 45 protrude from the threaded sleeve 46 which is fitted into appropriate recesses of both housing sections. This threaded sleeve 46 serves as a mounting for the excess current switch.

A trip shaft 47 is rotatably journalled in the housing and a trip lever 48 is rigidly secured to the shaft. This trip lever 48 has a recess into which a free arm 49' of the lever 24 engages with a retaining member 50 and braces itself against the edge 48 of that recess.

Furthermore, as shown in FIIG. 2 an arm 51 in the form of a compensation bimetal strip is secured to the trip shaft 47. A torsion spring 52 maintains the arm 51 in engagement with a member 53 the other end of which engages the leg 12 of the bimetal strip 7. An adjustment screw 54 serves for precise setting of the bimetal strip 7.

The lever 20 has a protuberance 55 capable of cooperating with a housing stop 56. The contact pressure is generated by a torsion spring 57 disposed on a bend 58 of the lever 24 and supported at one end on the pin 22 and at the other end by a bend 59 of the lever 24. On the pin 22 there is a torsion spring 60 one end of which engages the cross member 21 of the lever 20 while the other end rests against the lever 24.

A coupling lever 61 is rotatably disposed on the bearing p in 25. The coupling lever 61 is provided with an elongate slot 62 into which a peg 63 in the form of a hollow rivet secured to the control rod 37' engages.

The excess current switch illustrated operates as follows:

When the bimetal strip 7 is heated by an excess current its leg 12 is bent to the right as shown in FIG. 2. Since the excess current is of opposite direction in the two legs 11, 12 of the bimetal strip 7 an electrodynamic force acts on the leg 12 which also bends the leg 12 to the right as shown in FIG. 2. The leg 12 displaces the member 53 rightwardly in such manner that the arm 51 and thus the trip shaft 47 is thereby rotated in counter-clockwise direction. During this rotation the trip lever 48 secured to the trip shaft 47 releases the free arm 49 of the lever 24 so that the trip spring 33 pivots the lever 24 clockwise about the bearing pin 25. The elbow lever breaks and its lever 20 lifts the contact bridge 18 and its contacts 17 off the fixed contacts 15, 16 thus interrupting the circuit within the excess current switch. Since the force of the relaxed trip spring 33 is then weaker than the force of the tensioned spring 43 the latter overcomes the force of the trip spring 33, pivots the latch 30 clockwise with the aid of the protuberance 36 and shifts the push button 39 and the control rod 37 into the switched off position shown in FIG. 3. By means of the peg 63, the coupling lever 61 and the bearing pin 25 the elbow lever is also brought into the position of FIG. 3. The contact bridge 18 and its contacts 17 are lifted off the contacts 15, 16 even when, during thermal trip, the push button 39 is retained in the FIG. 1 position (trip-free release).

The excess current switch can also be tripped manually. When a tractive force is exerted on the push button 39 the protuberance 36 of the control rod 37 exerts a pressure on the ramp 35 of the latch 30 and pivots the latch against the force of the trip spring 33 in clockwise direction as shown in FIG. 1 until the bearing pin 25 of the lever 24 is released by the latch 30. The elbow joint can now break, the contact bridge 18 thus being lifted oi? the fixed contacts 15, 16.

In order to switch the switch from the off to the on position the push button 39 is pushed into the housing. When this is done first the drive member 42 and then the recess 41 of the control rod 37 act on the bearing pin 25 of the lever 24 so that the lever is moved downwardly. Thereby the free arm 49 of the lever 24 first engages into the recess of the trip lever 48 whereupon the lever 24 is pivoted anticlockwise about this detent site and the elbow lever is cocked. The torsion spring 60 thereby urges the lever 20 of the elbow lever and the pin 19 rightwarlly, as shown in FIG. 3, in its grooves 27 such that this pin 19 is placed against the detent 28 of the grooves 27. In this position the movable contacts 17 of the contact bridge 18 do not yet contact the fixed contacts 15, 16. Due to the slots 23 the lever 24 can be pivoted further in anticlockwise direction about its detent site. During this movement the projection 55 of the lever 20 meets the housing stop 56 whereby the lever 20 is pivoted in clockwise direction and the pin 19 slides off the detent 28 so that, by the action of the torsion spring 57 effecting the contact pressure the contact bridge 18 with its movable contacts 17 is jerked into contact with the fixed contacts 15, 16 and instantaneous connection is thus achieved.

In FIGS. and 6 there are shown three individual switches, each being of the type shown in FIGS. 1 to 4, and combined to form a multipole excess current switch. Insulating plates 64 are provided between the three individual switches so as to separate the connection chambers 65 of the individual switches. In the two outer individual switches insulating elements 66 for covering are inserted into the recesses present.

Only the central individual switch has a push button 39. The bearing pin 25 of the lever 24 of the central individual switch is extended into the outer individual switches and carries within each outer switch a lever 24. The latch 30 and the push button 39 with the control rod 37 as well as the coupling lever 61 are present only in the central switch. For this reason in the outer individual switches the trip spring 33 has its upper end secured to the housing. Each of the three individual switches has its own trip shaft 47. The respective trip shafts of the individual switches are interconnected by coupling strips which are inserted in appropriate slits of the trip shafts 47. The trip tolerances which appear in this way are avoided by the retaining nose 50 of the free arm 49 of the lever 24 being so constructed that when only one individual switch trips the nose 50 rotates the trip shaft 47 so far that the other individual switches can also trip. All the individual switches switch on or off simultaneously. Upon single pole tripping the other individual switches also switch olf.

I claim:

1. A single or multipole push button actuated excess current switch having a thermal and/or electromagnetic trip, such a switch comprising a housing, a pivoted lever arrangement, a contact bridge, said contact bridge being connected to the push button by means of said pivoted lever arrangement, the pivoted lever arrangement including' first and second levers, a pin and slot arrangement, said pin and slot arrangement interconnecting said first and second levers, the first lever being associated with the push button and being in the form of a bell crank which is pivotably mounted by means of a first pin adapted to be guided for transverse displacement in a surface of the housing defining a first groove, the first lever having a free end which is supported by a member which is adapted to be actuated by the thermal and/or the electromagnetic trip, the second lever being pivotally connected to the contact bridge by means of a second pin adapted to be guided for transverse movement in a surface of the housing defining a second groove, the surface defining said second groove being provided with a detent which is engaged by the second pin during switching on of the switch, the second lever being provided with a protuberance which is engageable with a stop on the housing to cause the second pin to be disengaged from the detent, a spring for biasing the second lever in the region of its interconnection with the first lever in a direction away from the first lever and a pivotally mounted latch plate which in the switched on position of the switch supports the first pin and which is connected to the lever arrangement so that upon tripping the first and second levers pivot relative to one another whereby the contact bridge is displaced to the switched otf position of the switch.

2. An excess current switch according to claim 1 in which the spring is in the form of a torsion spring having one end supported on the first lever and the other end thereof in contact with the second lever.

3. An excess current switch according to claim 1 which includes a trip spring, said trip spring being connected to the second lever, and a further torsion spring, said further torsion spring being arranged on the pin of the pin and slot connection between the first and second levers, said further torsion spring having one end connected with the first lever and the other end thereof connected to the second lever.

4. An excess current switch according to claim 1 which includes a coupling lever, said coupling lever being provided on the first pin, the said coupling lever defining an elongate slot engageable by a peg secured to a control rod which is rigidly connected to the push button, the control rod having a protuberance at the end thereof remote from the push button, the said protuberance being adapted to engage an inclined surface of the latch in the switched on position of the switch.

5. An excess current switch according to claim 1 in which said member adapted to be actuated by the thermal and/ or electromagnetic trip is in the form of a trip lever secured to a trip shaft, the trip lever defining an indentation which is engageable by the said free arm of the first lever, the switch further including an arm in the form of a compensation bimetal strip which is secured to the trip and upon which a bimetal strip of the thermal trip is adapted to act.

6. An excess current switch according to claim 5 in which the bimetal strip is U-shaped, with the two legs of the U being spaced so that they electrodynamically influence one another.

7. An excess current switch according to claim 1 in which the housing comprises two sections separated by a partition wall with the switching mechanism being disposed in one section and the trip mechanism being disposed in the other of the sections.

8. An excess current switch according to claim 7 in which the two sections define registering recesses in which the partition member is secured.

9. A multipole excess current switch according to claim 1 which includes a plurality of housings each having a trip mechanism and a switching mechanism therein, one of the housings having a push button associated therewith, the first levers of all the housings having a common first pin which extends through all the housings, each housing further being provided with a trip shaft which is connected to the trip shafts of the other housings and those housings not being provided with a push button having a trip spring having one end engaged with the first lever and the other end thereof secured to its associated housing.

' References Cited v UNITED STATES PATENTS 7. 2,958,751

11/1960 Camp 3s7 66 r 3,179,757 4/1965 Brandenberg 335-43 0 3,307,002 2/1967 Cooper 335-23 3,307,122 2/1967 Ellenberger; 335-164 3,451,016 6/1969 Ellenberger 335-23 3,629,763 12/1971 Walling 337-66 HAROLD BROOME, Primary Examiner U.S. c1. X.R. ass-43; 337-66 7 

